scholarly journals Palaeotopography concerning sea level changes to rethink past human activities in central Dalmatian islands area, Adriatic Sea

2018 ◽  
pp. 143-156
Author(s):  
Tomaž Podobnikar
Keyword(s):  
Sea Level ◽  
Landscape Archaeology ◽  
Environmental Conservation ◽  
Sea Level Changes ◽  
The Past ◽  
Gis Tools ◽  
Data Quality Assessment ◽  
Level Data ◽  
Digital Elevation ◽  
Elevation Model

Environmental conditions and access to natural resources are important factors for human behaviour and choices about where to make settlements. This important information must be understood and abstracted into appropriate spatial datasets, so as to be modelled in geographic information systems (GIS). The main objective is to design and realize a seamless integrated digital elevation model (DEM) from several data sources, including bathymetry. The important focus of this paper is to collect and interpret the sea level data for the Central Dalmatian islands over the past 15,000 years, describing the entire case study’s implementation in terms of hydrology, landscape archaeology, geodesy, data quality assessment, and spatial analysis. The results demonstrate that the proposed model has the potential to rethink the archaeological theories of settlement patterns in the studied area. The limitation of the proposed study is a lower quality of bathymetric datasets, and the determination of the historical sea level due to a number of uncertain factors. The work has profound implications in terms of the developed GIS tools that make it possible to generate reliable datasets and simulate various scenarios, as well as for a non-destructive prediction of the past archaeological landscapes. The solution may help increase awareness about cultural heritage, environmental conservation, and climate change.

scholarly journals Quaternary Coastal Landscape Evolution and Sea-Level Rise: An Example from South-East Sicily

Geosciences ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 506
Author(s):  
Salvatore Distefano ◽  
Fabiano Gamberi ◽  
Laura Borzì ◽  
Agata Di Stefano
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Late Quaternary ◽  
Depositional Environments ◽  
Sea Level Changes ◽  
Seismic Profiles ◽  
Bathymetric Range ◽  
Digital Elevation ◽  
Elevation Model ◽  
High Resolution Bathymetry

Coastal depositional environments are the site of complex interactions between continental and marine processes. Barrier islands are highly dynamic coastal systems, typical of these transitional environments, and are affected by sea level changes and the accumulation of transgressive deposits with the landwards migration of the coast. The offshore of Marzamemi (Syracuse Province, Sicily), in the south-eastern portion of the Hyblean foreland, represents an excellent site for the study of transgressive deposits and their connection with the sea-level changes. The available dataset consisted of new high-resolution bathymetry (Multibeam), whose description and interpretation through a Digital Elevation Model (DEM) was integrated with a grid of eighteen seismic profiles (SPARKER). In the investigated bathymetric range, from about −5 m to −60 m, a sensibly different morphological setting between the northern and southern sectors was evident. Within the whole study area, three bathymetric contours (−45 m, −35 m and −20) were identified and assumed as the markers of the main locations of the paleo-coastlines during the recent changes in the sea level. Along the northern sector, three submerged barrier-lagoon systems developed on a calcarenite substratum, marking important steps of the Late Quaternary sea-level rise. They coexisted with numerous karst forms (poljes and dolines). In the southern sector the transgressive environmental evolution was significantly different and submerged lagoons did not form. Here the outcropping calcarenite substratum was affected by the development of paleo-rivers and karsts structures, a tract in common along with many Mediterranean carbonate coastal areas.

Origin and Geomorphology

2006 ◽  
Author(s):  
Thomas S. Bianchi
Keyword(s):  
Sea Level ◽  
Rate Of Change ◽  
Interglacial Period ◽  
Continental Margins ◽  
Before Present ◽  
Sea Level Changes ◽  
The Past ◽  
Constant Rate ◽  
Geologic Record ◽  
The U.S

Geologically speaking, estuaries are ephemeral features of the coasts. Upon formation, most begin to fill in with sediments and, in the absence of sea level changes, would have life spans of only a few thousand to tens of thousands of years (Emery and Uchupi, 1972; Schubel, 1972; Schubel and Hirschberg, 1978). Estuaries have been part of the geologic record for at least the past 200 million years (My) BP (before present; Williams, 1960; Clauzon, 1973). However, modern estuaries are recent features that only formed over the past 5000 to 6000 years during the stable interglacial period of the middle to late Holocene epoch (0–10,000 y BP), which followed an extensive rise in sea level at the end of the Pleistocene epoch (1.8 My to 10,000 y BP; Nichols and Biggs, 1985). There is general agreement that four major glaciation to interglacial periods occurred during the Pleistocene. It has been suggested that sea level was reduced from a maximum of about 80 m above sea level during the Aftoninan interglacial to 100 m below sea level during the Wisconsin, some 15,000 to 18,000 y BP (figure 2.1; Fairbridge, 1961). This lowest sea level phase is referred to as low stand and is usually determined by uncovering the oldest drowned shorelines along continental margins (Davis, 1985, 1996); conversely, the highest sea level phase is referred to as high stand. It is generally accepted that low-stand depth is between 130 and 150 m below present sea level and that sea level rose at a fairly constant rate until about 6000 to 7000 y BP (Belknap and Kraft, 1977). A sea level rise of approximately 10 mm y−1 during this period resulted in many coastal plains being inundated with water and a displacement of the shoreline. The phenomenon of rising (transgression) and falling (regression) sea level over time is referred to as eustacy (Suess, 1906). When examining a simplified sea level curve, we find that the rate of change during the Holocene is fairly representative of the Gulf of Mexico and much of the U.S. Atlantic coastline (Curray, 1965).

scholarly journals Strengths of Exaggerated Tsunami-Originated Placenames: Disaster Subculture in Sanriku Coast, Japan

2019 ◽  
Vol 8 (10) ◽  
pp. 429 ◽  
Author(s):  
Yuzuru Isoda ◽  
Akio Muranaka ◽  
Go Tanibata ◽  
Kazumasa Hanaoka ◽  
Junzo Ohmura ◽  
...  
Keyword(s):  
Low Frequency ◽  
Local Area ◽  
Local Communities ◽  
Sanriku Coast ◽  
The Past ◽  
Disaster Experience ◽  
Digital Elevation ◽  
Disaster Subculture ◽  
Group Interviews ◽  
Elevation Model

Disaster-originated placename is a kind of disaster subculture that is used for a practical purpose of identifying a location while reminding the past disaster experience. They are expected to transmit the risks and knowledge of high-risk low-frequency natural hazards, surviving over time and generations. This paper compares the perceptions to tsunami-originated placenames in local communities having realistic and exaggerated origins in Sanriku Coast, Japan. The reality of tsunami-originated placenames is first assessed by comparing the tsunami run-ups indicated in the origins and that of the tsunami in the Great East Japan Earthquake 2011 using GIS and digital elevation model. Considerable proportions of placenames had exaggerated origins, but the group interviews to local communities revealed that origins indicating unrealistic tsunami run-ups were more believed than that of the more realistic ones. We discuss that accurate hazard information will be discredited if it contradicts to the people’s everyday life and the desire for safety, and even imprecise and ambiguous information can survive if it is embedded to a system of local knowledge that consistently explains the various facts in a local area that requires explanation.

25 years of movement monitoring on South Peak, Turtle Mountain: understanding the hazard

2009 ◽  
Vol 46 (3) ◽  
pp. 256-269 ◽  
Author(s):  
Corey R. Froese ◽  
Francisco Moreno ◽  
Michel Jaboyedoff ◽  
David M. Cruden
Keyword(s):  
Monitoring Program ◽  
Rock Avalanche ◽  
Light Detection And Ranging ◽  
Short Term ◽  
The Past ◽  
Digital Elevation ◽  
Government Project ◽  
Elevation Model ◽  
Movement Monitoring ◽  
Deep Fractures

In 1981, an Alberta Government project upgraded the monitoring of South Peak, Turtle Mountain, on the south margin of the 1903 Frank Slide. The monitoring program aimed at understanding the rates of deformation over large, deep fractures encompassing South Peak and predicting a second large rock avalanche on the mountain. The monitoring program consisted of a complement of static ground points and remotely monitored targets measured periodically, and climatic, microseismic, and deformation data collected automatically on daily intervals and archived. In the late 1980s, developmental funding for the monitoring program ceased and some of the installations fell into disrepair. Between May 2004 and September 2006, readings from the remaining functional monitoring points were compiled and interpreted. In addition, readings compiled previously were re-interpreted based on a more recent understanding of short-term movement patterns and climatic influences. These observations were compared with recent observations from an airborne light detection and ranging (LiDAR) digital elevation model and field photographs to give more precise estimates of the overall rates, extent, and patterns of motion for the past 25 years.

scholarly journals New elevation data triple estimates of global vulnerability to sea-level rise and coastal flooding

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Scott A. Kulp ◽  
Benjamin H. Strauss
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
High Tide ◽  
Water Levels ◽  
Low Carbon ◽  
Digital Elevation ◽  
Elevation Data ◽  
Global Mean Sea Level ◽  
Elevation Model ◽  
Global Mean

Abstract Most estimates of global mean sea-level rise this century fall below 2 m. This quantity is comparable to the positive vertical bias of the principle digital elevation model (DEM) used to assess global and national population exposures to extreme coastal water levels, NASA’s SRTM. CoastalDEM is a new DEM utilizing neural networks to reduce SRTM error. Here we show – employing CoastalDEM—that 190 M people (150–250 M, 90% CI) currently occupy global land below projected high tide lines for 2100 under low carbon emissions, up from 110 M today, for a median increase of 80 M. These figures triple SRTM-based values. Under high emissions, CoastalDEM indicates up to 630 M people live on land below projected annual flood levels for 2100, and up to 340 M for mid-century, versus roughly 250 M at present. We estimate one billion people now occupy land less than 10 m above current high tide lines, including 230 M below 1 m.

Middle and Late Holocene Sea-Level Changes in Eastern Maine Reconstructed from Foraminiferal Saltmarsh Stratigraphy and AMS 14C Dates on Basal Peat

1999 ◽  
Vol 52 (3) ◽  
pp. 350-359 ◽  
Author(s):  
W.Roland Gehrels
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Tidal Range ◽  
Sea Level Changes ◽  
The Past ◽  
Amplitude Fluctuations ◽  
Vertical Distributions ◽  
Low Amplitude ◽  
Long Term Trend

A relative sea-level history is reconstructed for Machiasport, Maine, spanning the past 6000 calendar year and combining two different methods. The first method establishes the long-term (103 yr) trend of sea-level rise by dating the base of the Holocene saltmarsh peat overlying a Pleistocene substrate. The second method uses detailed analyses of the foraminiferal stratigraphy of two saltmarsh peat cores to quantify fluctuations superimposed on the long-term trend. The indicative meaning of the peat (the height at which the peat was deposited relative to mean tide level) is calculated by a transfer function based on vertical distributions of modern foraminiferal assemblages. The chronology is determined from AMS 14C dates on saltmarsh plant fragments embedded in the peat. The combination of the two different approaches produces a high-resolution, replicable sea-level record, which takes into account the autocompaction of the peat sequence. Long-term mean rates of sea-level rise, corrected for changes in tidal range, are 0.75 mm/yr between 6000 and 1500 cal yr B.P. and 0.43 mm/yr during the past 1500 year. The foraminiferal stratigraphy reveals several low-amplitude fluctuations during a relatively stable period between 1100 and 400 cal yr B.P., and a sea-level rise of 0.5 m during the past 300 year.

Holocene Relative Sea Level Changes along the Seattle Fault at Restoration Point, Washington

2000 ◽  
Vol 54 (3) ◽  
pp. 384-393 ◽  
Author(s):  
Brian L. Sherrod ◽  
Robert C. Bucknam ◽  
Estella B. Leopold
Keyword(s):  
Sea Level ◽  
Environmental Changes ◽  
Hanging Wall ◽  
Sea Level Changes ◽  
Diatom Assemblages ◽  
Recent Event ◽  
Plant Seed ◽  
The Past ◽  
The One ◽  
Fossil Diatoms

At a marsh on the hanging wall of the Seattle fault, fossil brackish water diatom and plant seed assemblages show that the marsh lay near sea level between ∼7500 and 1000 cal yr B.P. This marsh is uniquely situated for recording environmental changes associated with past earthquakes on the Seattle fault. Since 7500 cal yr B.P., changes in fossil diatoms and seeds record several rapid environmental changes. In the earliest of these, brackish conditions changed to freshwater ∼6900 cal yr B.P., possibly because of coseismic uplift or beach berm accretion. If coseismic uplift produced the freshening ∼6900 cal yr B.P., that uplift probably did not exceed 2 m. During another event about 1700 cal yr B.P., brackish plant and diatom assemblages changed rapidly to a tidal flat assemblage because of either tectonic subsidence or berm erosion. The site then remained a tideflat until the most recent event, when an abrupt shift from tideflat diatoms to freshwater taxa resulted from ∼7 m of uplift during an earthquake on the Seattle fault ∼1000 cal yr B.P. Regardless of the earlier events, no Seattle fault earthquake similar to the one ∼1000 cal yr B.P. occurred at any other time in the past 7500 years.

Sea Level Fluctuation During the Past 6000 yr at the Coast of Mauritania

1974 ◽  
Vol 4 (3) ◽  
pp. 282-289 ◽  
Author(s):  
G. Einsele ◽  
D. Herm ◽  
H.U. Schwarz
Keyword(s):  
Sea Level ◽  
High Accuracy ◽  
Level Fluctuation ◽  
Sea Level Changes ◽  
Tidal Zone ◽  
The Past ◽  
Marine Terraces ◽  
Open Sea ◽  
Sea Level Fluctuation ◽  
Ecological Methods

In an area regarded to be very favorable for the study of Holocene sea level changes one or several eustatic (?) oscillations of sea have been found using sedimentological and ecological methods. After a maximum of +3 m during the Nouakchottian stage (= Middle Flandrian or Late Atlantic) about 5500 YBP a drop of sea to −3.5 ± 0.5 m about 4100 YBP is testified by stromatolitic algae indicating the former sea level within the tidal zone with high accuracy. This evidence is supported by the observation of post-Nouakchottian regressive and transgressive geologic sequences, by buried beach deposits and flooded hardgrounds, post-Nouakchottian marine terraces of different height and age, the cutting off of one large and several small bays from the open sea, etc. Possibly one or two smaller oscillations followed between 4000 and 1500 YBP (derived sea level curve Fig. 3).

Sea Level Changes in the Last Several Thousand Years, Penghu Islands, Taiwan Strait

1996 ◽  
Vol 45 (3) ◽  
pp. 254-262 ◽  
Author(s):  
Yue-Gau Chen ◽  
Tsung-Kwei Liu
Keyword(s):  
Sea Level ◽  
Taiwan Strait ◽  
Sea Level Changes ◽  
Relative Sea Level ◽  
Mollusk Shells ◽  
The Best Approximation ◽  
Level Data ◽  
Recent Position ◽  
Depositional Age ◽  
Penghu Islands

AbstractHolocene shore-face and beach-face deposits form plains <5 m above present sea level along Taiwan Strait. We measured the 14C ages of detrital mollusk shells and coral in such deposits at the Penghu Islands. Twelve carbonate samples—mainly from the largest island, Makung—were dated. Age measurements for two coral samples and one mollusk sample from the same outcrop imply that the 14C ages of mollusk shells give the best approximation of depositional age. The highest Holocene relative sea level in the Penghu Islands occurred about 4700 years ago with a height about 2.4 m above the present sea level. Thereafter, relative sea level appreciably fell without detectable fluctuations to its recent position. Our sea level data are consistent with other studies from the central and western Pacific, except for the timing of peak sea level position. This variation may reflect local crustal response to hydroisostatic effects on the continental shelf.

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